Muscle Disease

Question 1

What are the main causes of myopathy disorders?

Answer 1

Inflammatory
Endocrine disorders
Electrolyte/ Metabolic disorders
Drugs/Toxins
Infection
Rhabdomyolysis

Question 2

How do muscle diseases usually present?

Answer 2

Muscle pain (myalgia)
Muscle weakness/tiredness
Stiffness
Abnormal blood tests

Question 3

What type of muscle disease are polymyositis and dermatomyositis?

Answer 3

Inflammatory

Question 4

What gender is more affected by inflammatory muscle disease?

Answer 4

Female:male 2:1

Question 5

What age group most commonly develop inflammatory muscle disease such as polymyositis or dermatomyositis?

Answer 5

Peak incidence ages 40-50 years

Question 6

There is an increased incidence of malignancy in inflammatory muscle disease. TRUE/FALSE?

Answer 6

TRUE

Question 7

What histological features can be seen on muscle biopsy in inflammatory muscle disease?

Answer 7

muscle fibre necrosis
degeneration
regeneration
inflammatory cell infiltrate

Question 8

What causes inflammatory muscle disease such as polymyositis or dermatomyositis?

Answer 8

cause is unknown

Question 9

Muscle weakness usually presents asymmetrically and gets better over the course of a few months. TRUE/FALSE?

Answer 9

FALSE
Insidious onset, worsening over months
Usually symmetrical, proximal muscles

Question 10

What activities do patients commonly struggle with when they have muscle weakness?

Answer 10

difficulty brushing hair

or climbing stairs

Question 11

What cutaneous sign can be present in dermatomyositis?

Answer 11

Gottrons sign
- erythematous macules over dorsum of digits, and can be over elbows and knees

Heliotrope rash
- erythema of the upper eyelids often with associated oedema and telangiectasia

Shawl sign
- erythematous macules on upper back, shoulders, and back of the neck. Can worsen with exposure to UV

Question 12

What other organ systems can be involved in inflammatory muscle disease

Answer 12

Lung:

• Interstitial lung disease (10%)
• Respiratory muscle weakness

Oesophageal:
- Dysphagia

Cardiac:
- Myocarditis

Other:
Fever, weight loss, Raynauds phenomenon, non- erosive polyarthritis

Question 13

By how much do inflammatory muscle diseases increase the rate of malignancy, and who is most at risk?

Answer 13

15% incidence in dermatomyositis
9% polymyositis

Risk greatest in men over 45 years

Question 14

Risk of malignancy occurs in what type of cancers when associated with inflammatory muscle disease?

Answer 14

Ovarian
breast
stomach
lung
bladder 
colon

Question 15

What symptoms would you expect to see in the history of patient with inflammatory muscle disease?

Answer 15

tired muscles
functional difficulty
muscle pain
weight loss
cough
breathlessness
Raynauds

Question 16

What underlying medical conditions should you be aware of when taking a history suggestive of inflammatory muscle disease?

Answer 16

thyroid disease

Question 17

What medications can cause inflammatory muscle disease?

Answer 17

steroids, statins

=> be aware of patients with underlying conditions that report taking these drugs in Hx

Question 18

What examinations would you carry out to aid the diagnosis of inflammatory muscle disease?

Answer 18

Confrontational testing
(Direct testing of power)

Isotonic testing
(30 second sit to stand test)

Question 19

What would you look for in the blood test results of a patient who you think has inflammatory muscle disease?

Answer 19

Muscle enzymes eg. Creatine kinase (CK)

Inflammatory markers

Electrolytes, calcium, PTH, TSH (to exclude other causes)

Autoantibodies: ANA, Anti-Jo-1

Question 20

What other investigations would you do to potentially diagnose inflammatory muscle disease?

Answer 20

Electromyography

Muscle biopsy
-Perivascular inflammation and muscle necrosis

MRI
-muscle inflammation, oedema, fibrosis and calcification

Question 21

What treatments can be used for inflammatory muscle disease?

Answer 21

Glucocorticoids
Azathioprine
Methotrexate
Ciclosporin
IV immunoglobulin
Rituximab

Question 22

What age group is commonly affected by polymyalgia rheumatica?

Answer 22

Occurs almost exclusively in those over 50 years

Question 23

What other condition is associated with polymyalgia rheumatica?

Answer 23

Associated with temporal arteritis/giant cell arteritis (15%)

Question 24

How do patients with polymyalgia rheumatica present clinically?

Answer 24

Ache in shoulder and hip girdle
=> Reduced movement of shoulders, neck and hips

Usually symmetrical

Morning stiffness

Fatigue/anorexia/Weight loss/fever

Muscle strength = NORMAL

Question 25

What symptoms would indicate polymyalgia rheumatica is coexisting with Giant cell/ temporal arteritis?

Answer 25

Headache
Scalp tenderness
Jaw claudication
Visual loss 
Tender, enlarged, non-pulsatile temporal arteries

Question 26

How is polymyalgia rheumatica treated? (with and without temporal arteritis)

Answer 26

Rapid/dramatic response to low dose steroids

if temporal arteritis present => higher steroid doses required

Gradual reduction in steroid dose over around 18 months to 2 years

Question 27

Fibromyalgia is associated with inflammation. TRUE/FALSE?

Answer 27

FALSE

Question 28

Which gender is more affected by fibromyalgia?

Answer 28

Commoner in women (F:M, 6:1)

May begin after emotional or physical trauma

Question 29

What symptoms are common in fibromyalgia?

Answer 29

Pain neck, shoulders, lower back, chest wall

Sensation of swelling

Fatigue and poor, unrefreshing sleep

Pins and needles/tingling,

Abdominal pain (IBS)

headaches, depression, poor concentration and memory

Question 30

Symptoms in fibromyalgia worsen with exertion, fatigue and stress. TRUE/FALSE?

Answer 30

TRUE

Question 31

What criteria need to be met for a diagnosis of fibromyalgia?

Answer 31

Widespread pain and associated symptoms

Symptoms present at same level for at least 3 months or more

No other condition otherwise explains the pain

Question 32

What is used to treat fibromyalgia?

Answer 32

NON-medical:

• Patient education
• Graded exercise programme
• Cognitive behavioural therapy
• Complementary medicine eg. acupuncture

Medicines:

• Anti-depressants eg. Tricyclics, SSRIs
• Analgesia
• Gabapentin and pregabalin